2.7 Elastic potential energy EPE

2.7 Elastic potential energy EPE

Starter activity

What is the type of energy that stored in the bow?

Multiple Select

Do you think that the spring will return to its original shape after being stretched or compressed?

• Yes

• No

Elastic energy

When the object changes, its shape deforms, it stores elastic potential energy which is transferred to another type of energy.

Explain how the fan works.

As we wind up the rubber, it stores elastic potential energy. When we let it go this stored elastic energy transfers to kinetic and the fan works.

Task 1

Watch the video to answer the next question.

Multiple Select

As the ball hits the ground, ..................energy is transferred to ....................... enrgy.

• gravitational to kinetic

• kinetic to chemical

• kinetic to elastic

• kinetic to gravitational

Activity 2

Investigate about how the height from Which a ball is dropped affects the height it bounces back. Taht was the question for the investigation.

The first step is to ask a question:

How does the height from which a ball is dropped affects the height to which it bounces back.

Step 2 : prediction

What is your prediction?

Step 2 : prediction

As higher the position from which the ball is dropped, the higher it bounces back.

What is the next step in this investigation?

What is the next step in this investigation?

Collect evidence by carrying out an experiment.

Task 2

Watch the video and to answer the following questions.

Multiple Choice

When the ball is lifted up, it gained ...................... energy.

• elastic

• chemical

• gravitational

• kinetic

Multiple Choice

When the ball is falling down, the gravitational energy is transferred to .................................... energy.

• potential

• kinetic

• elastic

• chemical

Multiple Choice

As the ball hits the floor, its shape changes. We call this as "the ball deforms". At this point the ball stores ............................ energy.

• gravitational

• elastic

• kinetic

• chemical

Multiple Select

After collecting evidence, we need to present the data in tables and graphs.

• true

• false

Open Ended

Challenge question:

Why does the ball always bounce back to a height that is less than the height it was dropped from?

If you drop a ball from a height , it bounces back up to a height that it less than the height it was dropped from.

Because when it hits the ground, it wastes some energy as heat energy, so not all EPE it gains transferred to KE.

Bungee jumping

Watch the video to explain the energy transfer that takes place.

Multiple Choice

Plenary

1. A student is playing with an elastic band, stretching it, and letting it go.

As she stretches it , the .......................... energy is transferred to ......................energy.

• potential to elastic

• kinetic to elastic

• elastic to kinetic

Multiple Choice

Plenary

2. A student is playing with an elastic band, stretching it, and letting it go.

As she pulls it back more, it wii go ......................

• closer

• further